Air maintenance tire and pumping tube assembly and method

ABSTRACT

A tire has an elongate profiled sidewall groove extending into a first tire sidewall from an outward first sidewall surface. An elongate air tube is positioned within the elongate sidewall groove in contact with the groove sidewalls, the air tube having an external surface configuration corresponding with and seating within the internal sidewall configuration defining the sidewall groove. The air tube when subject to outward originating impinging force collapses from an expanded unstressed configuration into a collapsed configuration to allow the tube to insert through the groove entry opening and expand outwardly once within the sidewall groove to its unstressed configuration. The configuration of the groove sidewalls capture the air tube within the groove in its expanded unstressed configuration to prevent separation of the tube from the tire during use.

FIELD OF THE INVENTION

The invention relates generally to air maintenance tires and, morespecifically, to an air maintenance tire and pumping tube assemblytherefore and method of assembly.

BACKGROUND OF THE INVENTION

Normal air diffusion reduces tire pressure over time. The natural stateof tires is under inflated. Accordingly, drivers must repeatedly act tomaintain tire pressures or they will see reduced fuel economy, tire lifeand reduced vehicle braking and handling performance. Tire PressureMonitoring Systems have been proposed to warn drivers when tire pressureis significantly low. Such systems, however, remain dependant upon thedriver taking remedial action when warned to re-inflate a tire torecommended pressure. It is a desirable, therefore, to incorporate anair maintenance feature within a tire that will re-inflate the tire inorder to compensate for any reduction in tire pressure over time withoutthe need for driver intervention.

SUMMARY OF THE INVENTION

In one aspect of the invention, a tire is provided having an elongatesidewall groove extending into a first tire sidewall from an outwardfirst sidewall surface; the sidewall groove having an outer groove entryopening, a groove entry chamber axially inward from the groove entryopening defined by divergent entry chamber sidewalls, and a grooveprimary chamber axially inward from the groove entry chamber. The grooveentry chamber sidewalls and the groove primary chamber sidewallsintersect to form at the intersection a detent channel. An elongate airtube is positioned within the elongate sidewall groove in contact withthe groove primary chamber sidewalls. The air tube has an externalsurface configuration corresponding with the sidewall configurationdefining the elongate sidewall groove.

In another aspect, the air tube body has an external protrusionconfigured and dimensioned to register and seat within the detentchannel of the sidewall groove.

The air tube, in yet another aspect of the invention, is formed ofresilient material operative when subject to outward originatingimpinging force on the air tube to collapse from an expanded unstressedconfiguration into a collapsed configuration to allow the tube to insertthrough the groove entry opening and expand outwardly once within thesidewall groove to its unstressed configuration.

According to another aspect, a method for inserting a so-configured airtube into a sidewall groove of a tire is provided including collapsingthe air tube from an expanded unstressed configuration into a collapsedconfiguration to allow the tube to insert through the groove entryopening and expanding the tube outwardly once within the sidewall grooveto its unstressed configuration.

DEFINITIONS

“Aspect ratio” of the tire means the ratio of its section height (SH) toits section width (SW) multiplied by 100 percent for expression as apercentage.

“Asymmetric tread” means a tread that has a tread pattern notsymmetrical about the center plane or equatorial plane EP of the tire.

“Axial” and “axially” means lines or directions that are parallel to theaxis of rotation of the tire.

“Chafer” is a narrow strip of material placed around the outside of atire bead to protect the cord plies from wearing and cutting against therim and distribute the flexing above the rim.

“Circumferential” means lines or directions extending along theperimeter of the surface of the annular tread perpendicular to the axialdirection.

“Equatorial Centerplane (CP)” means the plane perpendicular to thetire's axis of rotation and passing through the center of the tread.

“Footprint” means the contact patch or area of contact of the tire treadwith a flat surface at zero speed and under normal load and pressure.

“Groove” means an elongated void area in a tire wall that may extendcircumferentially or laterally about the tire wall. The “groove width”is equal to its average width over its length. A grooves is sized toaccommodate an air tube as described.

“Inboard side” means the side of the tire nearest the vehicle when thetire is mounted on a wheel and the wheel is mounted on the vehicle.

“Lateral” means an axial direction.

“Lateral edges” means a line tangent to the axially outermost treadcontact patch or footprint as measured under normal load and tireinflation, the lines being parallel to the equatorial centerplane.

“Net contact area” means the total area of ground contacting treadelements between the lateral edges around the entire circumference ofthe tread divided by the gross area of the entire tread between thelateral edges.

“Non-directional tread” means a tread that has no preferred direction offorward travel and is not required to be positioned on a vehicle in aspecific wheel position or positions to ensure that the tread pattern isaligned with the preferred direction of travel. Conversely, adirectional tread pattern has a preferred direction of travel requiringspecific wheel positioning.

“Outboard side” means the side of the tire farthest away from thevehicle when the tire is mounted on a wheel and the wheel is mounted onthe vehicle.

“Peristaltic” means operating by means of wave-like contractions thatpropel contained matter, such as air, along tubular pathways.

“Radial” and “radially” means directions radially toward or away fromthe axis of rotation of the tire.

“Rib” means a circumferentially extending strip of rubber on the treadwhich is defined by at least one circumferential groove and either asecond such groove or a lateral edge, the strip being laterallyundivided by full-depth grooves.

“Sipe” means small slots molded into the tread elements of the tire thatsubdivide the tread surface and improve traction, sipes are generallynarrow in width and close in the tires footprint as opposed to groovesthat remain open in the tire's footprint.

“Tread element” or “traction element” means a rib or a block elementdefined by having a shape adjacent grooves.

“Tread Arc Width” means the arc length of the tread as measured betweenthe lateral edges of the tread.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described by way of example and with reference tothe accompanying drawings in which:

FIG. 1 is an exploded isometric view of a tire, rim, and peristaltictube assembly.

FIG. 2 is a side view of the tire with the peristaltic tube assemblywithin a tire sidewall.

FIG. 3A is an isometric view of an outlet device component showing ofthe tube assembly.

FIG. 3B is a plan view of the outlet device.

FIG. 3C is a section view through the outlet device taken along the line3C-3C of FIG. 3B.

FIG. 4A is an isometric view of an inlet device component of the tubeassembly.

FIG. 4B is an isometric view of the inlet device with the filter sleevein phantom.

FIG. 4C is an isometric view of the inlet device component showing airintake schematically and the tube of the device in phantom.

FIG. 4D is a sectional view through the inlet device taken along theline 4D-4D of FIG. 4B.

FIG. 4E is a section view through the inlet device taken along the line4E-4E of FIG. 4C.

FIG. 5A is a side elevation view of the tire and peristaltic tubeassembly shown schematically rotating against a road surface.

FIG. 5B is a side elevation view of the tire and peristaltic tubeassembly shown sequentially subsequent to the position of FIG. 5A.

FIG. 6A is a transverse section view through the tire and peristaltictube assembly.

FIG. 6B is an enlarged section view of the portion of the tire beadregion, rim, and a non-collapsed peristaltic tube segment as identifiedin FIG. 6A.

FIG. 7A is a transverse section view through the tire and peristaltictube assembly with the tube in the collapsed configuration.

FIG. 7B is an enlarged section view of a portion of the tire beadregion, rim, and collapsed tube segment identified in FIG. 7A.

FIG. 8A is an enlarged sectional exploded view of the tube andtube-receiving groove within the tire sidewall.

FIGS. 8B and 8C are subsequent sequential sectional views to FIG. 8Ashowing insertion of the tube into the sidewall groove.

FIG. 8D is a fragmented exploded view of the tube and sidewall groovecorresponding to FIG. 8A.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1, 2, and 6A, a tire assembly 10 includes a tire 12,a peristaltic pump assembly 14, and a tire rim 16. The tire mounts inconventional fashion to a pair of rim mounting surfaces 18, 20 adjacentouter rim flanges 22, 24. The rim flanges 22, 24, each have a radiallyoutward facing flange end 26. A rim body 28 supports the tire assemblyas shown. The tire is of conventional construction, having a pair ofsidewalls 30, 32 extending from opposite bead areas 34, 36 to a crown ortire tread region 38. The tire and rim enclose a tire cavity 40.

As seen from FIGS. 1, 2, 5A, 5B, 6A, 6B and 8D the peristaltic pumpassembly 14 includes an annular air tube 42 that encloses an annularpassageway 43. The tube 42 is formed of a resilient, flexible materialsuch as plastic or rubber compounds that are capable of withstandingrepeated deformation cycles wherein the tube is deformed into aflattened condition subject to external force and, upon removal of suchforce, returns to an original condition. The tube passageway 43 isgenerally elliptical in section and is of a diameter sufficient tooperatively pass a volume of air sufficient for the purposes describedherein and allowing a positioning of the tube in an operable locationwithin the tire assembly as will be described. In the configurationshown, the tube 42 is elongate and circular. The tube 42 is asymmetricabout an elongate major axis and is constructed having an outward flatend surface 44, a tapered protruding outward portion 46, and a main bodyportion 48. The protruding portion 46 of the tube 42 is defined bybeveled surfaces 52, 54 that diverge from the flat tube surface 44 to anarcuate outward surface 56 of the main body portion 48 of the tube 42.At the intersection of the beveled surfaces 52, 54 and outer surface 56of the main body portion 48 a pair of shoulders 57, 59, respectively,are formed which extend the length of tube 42 on opposite respectivesides of protruding portion 46.

An elongate groove 58 is formed to extend into an axially outwardsurface of a sidewall such as sidewall 30, preferably in the geometricform of an annular ring. The other sidewall may be grooved or bothsidewalls if so desired. The groove 58 has an internal sectional profilecomplementary with the external geometry of the tube 42, and includes anentry opening 60 exposed to the outer surface 61 of the sidewall 30. Thegroove 58 is formed to provide an entry chamber 62 adjacent to andaxially inward of the opening 60 and a primary chamber 64 axially inwardfrom and adjacent to the entry chamber 62. The entry chamber 62 isdefined by beveled sidewalls 66, 68 diverging axially inward from theopening 60 and the primary chamber is defined by primary chambersidewalls 70. At the intersection of the beveled sidewalls 66, 68 andthe inward sidewalls 70 of the primary chamber a pair of shouldersdetent channels 72, 74, respectively, are formed which extend the lengthof groove 58 on opposite respective sides of the groove.

As referenced in FIG. 8A, the tube 42 has a transverse sectional widthlength L1 within a preferred range of 3.65 to 3.8 mm; a preferred heightof D1 within a range of 2.2 to 3.8 mm; a trailing end preferred width ofD3 within a range of 0.8 to 1 mm. The internal air passageway 43 isgenerally elliptical having a length L2 along a major axis within apreferred range of 2.2 to 2.3 mm, and a width D2 along a transverse axiswithin a preferred range of 0.5 to 0.9 mm. The tube 42 has an axialdistance L3 between the end surface 44 and the center of the passageway43 lying within a preferred range of 1.8 to 2 mm.

The groove 58 is of complementary internal geometry to accommodate closereceipt of the tube 42. As shown in FIG. 8A, the groove 58 isdimensionally compatible for receipt of the tube 42, and incorporatesdimensions D1, D3, L1, L3 within the preferred ranges previously setforth with respect to the tube 42. The primary chamber 64 is radiussedby a radius R1 lying within a preferred range of 1.1 to 1.9 mm. Thebeveled surfaces 66, 68 and complementary divergent surfaces 52, 54 ofthe tube 42 are sloped at generally an acute angle of approximately 45degrees.

As best seen from FIGS. 8A-D, insertion of the tube 42 into the groove58 is initiated by axially aligning the tube 42 with the entry opening60 of the groove 58; compressing the tube 42 in the direction of arrows76 so as to reduce the groove height, whereby collapsing the groove airpassageway 43; inserting the tube 42 laterally through the grooveopening 60 and into the space defined by entry chamber 62 and primarychamber 64; removing the compression force at arrows 76, thereby freeingthe tube 42 to expand outward into its nominal unstressed configurationof FIGS. 8A, 8C, and 8D and occupy the groove 58. The tube 42 is thuslocated within the groove 58 with external surfaces of the groovedisposed adjacent to corresponding complementary sidewalls defining thegroove 58. In the expanded, unstressed condition of the tube, theshoulders 57, 59 of the tube 42 register within the detent channels 72.74 formed at the intersection of groove sidewalls 66, 68 and 70. Soregistered, the divergent sides 52, 54 of the tube abut the entrychamber divergent sidewalls 66, 68, respectively, and thereby retain thetube 42 within the groove 58.

With reference to FIGS. 1, 2, 3A through 3C and 4A through E, theperistaltic pump assembly 14 further includes an inlet device 78 and anoutlet device 80 spaced apart approximately 180 degrees at respectivelocations along the circumferential air tube 42. The outlet device 80,as shown in FIGS. 3A through 3C, has a T-shaped configuration in whichconduits 82, 84 direct air to and from the tire cavity 40. An outletdevice housing 86 contains conduit arm extensions 88, 90 that integrallyextend at right angles from respective conduits 82, 84. Each of theconduit arms 88, 90 have external coupling ribs or barbs 92, 94 forretaining the conduits within disconnected ends of the air tube 42 inthe assembled condition. The housing 86 is formed having an externalgeometry that complements the groove 58 and includes a flat side 96along a generally oblong body 98. So configured, the housing 86 iscapable of close receipt into the groove 58 at its intended location.

The inlet device 78 as seen in FIGS. 1, 2, 4A through 4E includes anelongate outward porous filtering sleeve 100 encasing an internal intaketube 102. The outward sleeve 100 has an external geometry including atubular inward air passage body 102. The sleeve 100 is configured toprovide a bored tubular inward body 106 attached to an outward lobe body104. The intake tube 102 has multiple air intake openings 108 thereinwhich communicate with an axial air passageway extending through thetube 102. The inward body 106 is geometrically profiled to fit withinthe groove 58 with the lobe body 104 abutting against an outward surfaceof the tire sidewall. Air intake indicated by arrows 110 enters throughthe porous filtering sleeve 100 and the apertures 108 into the intaketube 102. Ends of the intake tube 102 are attached to the air tube 42residing within the groove 58 and the tube 102 directs intake air intothe tube 42 for pumping into the tire cavity.

As will be appreciated from FIGS. 1, 2, 6A, 6B, 7A and 7B, the pumpassembly 14 comprises the air tube 42 and inlet and outlet devices 78,80. Devices 78, 80 are affixed in-line to the air tube 42 at respectivelocations 180 degrees apart, is inserted into the groove 58. The groove58 is located at a lower sidewall region of the tire that, when the tire12 is mounted to the rim 16, positions the air tube 42 above the rimflange ends 26. FIG. 8B and 8C show the air tube 42 diametricallysqueezed and collapsed to accommodate insertion into the groove 58. Uponfull insertion, as shown in FIG. 8C, the air tube 42 fills the voidrepresented by the groove 58. Once fully inserted, the air passageway 43of the tube 42 elastically restores into an open condition to allow theflow of air along the tube during operation of the pump.

With continued reference to Referring to FIGS. 1, 2, 5A, 5B, 6A, 6B, 7A,7B, the inlet device 78 and the outlet device 80 are positioned withinthe circumference of the circular air tube 42 generally 180 degreesapart. The tire 12 with the tube 42 positioned within groove 58 rotatesin a direction of rotation 112, causing a footprint 114 to be formedagainst the ground surface 116. A compressive force 118 is directed intothe tire from the footprint 114 and acts to flatten a segment 120 of theair tube passageway 43 opposite the footprint 114 as shown at numeral120. Flattening of the segment 120 of the passageway 43 forces air fromthe segment along tube passageway 43 in the direction shown by arrow 122toward the outlet device 80.

As the tire continues to rotate in direction 112 along the groundsurface 116, the tube 42 will be sequentially flattened or squeezedopposite the tire footprint segment by segment in a direction oppositeto the direction of tire rotation 112. A sequential flattening of thetube passageway 43 segment by segment will result and cause evacuatedair from the flattened segments to be pumped in the direction 122 withintube passageway 43 to the outlet device 80 and from the outlet device 80to the tire cavity as shown at 124. A valve system to regulate the flowof air to the cavity when the air pressure within the cavity falls to aprescribed level is shown and described in pending U.S. patent applicantSer. No. 12/775,552, filed May 7, 2010, and incorporated herein byreference.

With the tire rotating in direction 112, flattened tube segments aresequentially refilled by air flowing into the inlet device 78 in thedirection 110 as shown by FIG. 5A. The inflow of air into the inletdevice 78 and then into the tube passageway 43 continues until theoutlet device 80, rotating counterclockwise as shown with the tirerotation, passes the tire footprint 114. FIG. 5B shows the orientationof the peristaltic pump assembly 14 in such a position. In the positionshown, the tube 42 continues to be sequentially flattened segment bysegment opposite the tire footprint by compressive force 118. Air ispumped in the clockwise direction 122 to the inlet device 78 where it isevacuated or exhausted outside of the tire. Passage of exhaust air asshown at 126 from the inlet device 78 is through the filter sleeve 100which is formed of a cellular or porous material or composite. Flow ofair through the sleeve 100 causes the sleeve 100 to be thus cleansed ofdebris or particulates. In the exhaust or reverse flow of air direction126, the sleeve 100 is cleansed of trapped accumulated debris orparticles within the porous medium. With the evacuation of pumped airout of the inlet device 78, the outlet device is in the closed positionand air does not flow to the tire cavity. When the tire rotates furtherin counterclockwise direction 112 until the inlet device 78 passes thetire footprint 114 (as shown in FIG. 5A), the airflow resumes to theoutlet device 80 and causes the pumped air to flow out and into the tirecavity 40. Air pressure within the tire cavity is thus maintained at adesired level.

The above-described cycle is then repeated for each tire revolution,half of each rotation resulting in pumped air going to the tire cavityand half of the rotation the pumped air is directed back out the inletdevice filter sleeve 100 to self-clean the filter. It will beappreciated that while the direction of rotation 112 of the tire 12 isas shown in FIGS. 5A and 5B to be counterclockwise, the subject tireassembly and its peristaltic pump assembly 14 will function in likemanner in a (clockwise) reverse direction of rotation as well. Theperistaltic pump is accordingly bi-directional and equally functionalwith the tire assembly moving in a forward or a reverse direction ofrotation.

A preferred location for the air tube assembly 14 is as shown in FIGS.5A, 5B, 6A, 6B, 7A and 7B. The tube 42 is located within the groove 58in a lower region of the sidewall 30 of the tire 12. So located, thepassageway 43 of the tube 42 is closed by compression strain bending thesidewall groove 58 within a rolling tire footprint as explained above.The location of the tube 42 in the sidewall 30 affords the user freedomof placement and avoids contact between the tube 42 and the rim 16. Thehigher placement of the tube 42 in the sidewall groove 58 uses the highdeformation characteristics of this region of the sidewall as it passesthrough the tire footprint to close the tube.

From the forgoing, it will be appreciated that the subject inventionprovides a bi-directionally peristaltic pump for air maintenance of atire. The circular air tube 42 flattens segment by segment and closes inthe tire footprint 114. The air inlet device 78 may include an outerfilter sleeve 100 formed of porous cellular material and thereby renderdevice 78 as self-cleaning. The outlet device 80 employs a valve unit(see co-pending U.S. patent application Ser. No. 12/775,552, filed May7, 2010, incorporated herein by reference). The peristaltic pumpassembly 14 pumps air under rotation of the tire in either direction,one half of a revolution pumping air to the tire cavity 40 and the otherhalf of a revolution pumping air back out of the inlet device 68. Theperistaltic pump assembly 14 may be used with a secondary tire pressuremonitoring system (TPMS) (not shown) of conventional configuration thatserves as a system fault detector. The TPMS may be used to detect anyfault in the self-inflation system of the tire assembly and alert theuser of such a condition.

The tire air maintenance system further incorporates a specifiedgeometric shape to the tube 42 which locks into the groove 48 andprevents inadvertent dislodgement of the tube during tire operation. Thetube 42 flattens into a compressed configuration and is insertedlaterally into the groove 58. Upon removal of the compression forces,the tube 42 resumes its original shape and fills the void represented bygroove 58. The tapered sides of the sidewalls defining the groove 58 incomplement with the like-tapered external sides of the groove preventany escape of the tube 42 through the smaller entryway of the groove 58.

It will thus be appreciated that, in the subject invention, an elongatesidewall groove 58, preferably in a circular configuration, extends intoone or both of the tire sidewalls from an outward sidewall surface. Eachsidewall groove 58 has an outer groove entry opening, a groove entrychamber axially inward from the groove entry opening defined bydivergent entry chamber sidewalls, and a groove primary chamber axiallyinward from the groove entry chamber. The groove entry chamber sidewallsand the groove primary chamber sidewalls intersect to form at theintersection a detent channel. The elongate air tube 42, likewise in apreferably circular configuration, is positioned within the elongatesidewall groove in contact or in close proximity with the groove primarychamber sidewalls. The air tube has an external surface configurationcorresponding with the sidewall configuration defining the elongatesidewall groove.

The air tube body 42 has an external protrusion 57, 59 configured anddimensioned to register and seat within the detent channels 72, 74 ofthe sidewall groove, to hold the air tube 42 in place within the groove.The air tube 42, being formed of resilient material, is capable whensubject to outward originating impinging force on the air tube ofcollapsing from an expanded unstressed configuration into a collapsedconfiguration to allow the tube to insert through the groove entryopening and expand outwardly once within the sidewall groove to itsunstressed configuration. The method for inserting the configured airtube 42 into the sidewall groove 58 includes collapsing the air tubefrom an expanded unstressed configuration into a collapsed configurationto allow the tube to be inserted through the groove entry opening and,once inserted, expanded outwardly to its unstressed configuration.

Variations in the present invention are possible in light of thedescription of it provided herein. While certain representativeembodiments and details have been shown for the purpose of illustratingthe subject invention, it will be apparent to those skilled in this artthat various changes and modifications can be made therein withoutdeparting from the scope of the subject invention. It is, therefore, tobe understood that changes can be made in the particular embodimentsdescribed which will be within the full intended scope of the inventionas defined by the following appended claims.

What is claimed is:
 1. A tire assembly comprising: a tire having a tirecavity, a first and a second sidewall extending to a tire tread region;an elongate sidewall groove extending into the first tire sidewall froman outward first sidewall surface; the sidewall groove having an outergroove entry opening, a groove entry chamber axially inward from thegroove entry opening defined by divergent entry chamber sidewalls, and agroove primary chamber axially inward from the groove entry chamberdefined by primary chamber sidewalls, the groove entry chamber sidewallsand the groove primary chamber sidewalls intersecting and forming at theintersection a detent channel substantially extending a longitudinallength of the sidewall groove; an elongate air tube positioned withinthe elongate sidewall groove in at least partial contacting engagementwith the groove primary chamber sidewalls, the air tube having aninternal air passageway; wherein the air tube has a primary air tubebody, the primary air tube body having an external surface configurationdefined by primary air tube body external sides substantially adjacentand extending in parallel with the groove primary chamber sidewalls; andwherein the primary air tube body having an axially outward air tubebody protrusion, air tube body protrusion having an external surfaceconfiguration defined by protrusion external sides substantiallyadjacent and extending in parallel with the groove entry chambersidewalls.
 2. The tire assembly of claim 1, wherein the primary air tubebody external sides and the air tube body protrusion external sidesintersect and form at the intersection a shoulder residing within thedetent channel of the sidewall groove.
 3. The tire assembly of claim 2,wherein the air tube and the sidewall groove extend along a commonsubstantially circular path.
 4. The tire assembly of claim 2, whereinthe air tube is formed of resilient material operative when subject tooutward originating impinging force on the air tube to collapse from anexpanded unstressed configuration into a collapsed configuration whereinthe air passageway is substantially closed.
 5. The tire assembly ofclaim 4, wherein the air tube is operative to resiliently resume theexpanded unstressed configuration upon removal of the impinging force.6. The tire assembly of claim 5, wherein the air tube in the expandedunstressed configuration has an expanded transverse dimension greaterthan a diametric dimension of the groove entry opening and the air tubein the collapsed configuration has a collapsed transverse dimension lessthan the diametric dimension of the groove entry opening.
 7. The tireassembly of claim 6, wherein the air tube substantially occupies avolumetric entirety of the sidewall groove.
 8. The tire assembly ofclaim 7, wherein the air passageway is substantially elliptical insection along a longitudinal axis oriented in an axial direction withinthe sidewall groove.
 9. The tire assembly of claim 1, wherein the airtube is asymmetrical in a radial tire direction.
 10. The tire assemblyof claim 9, wherein the air passageway is substantially elliptical insection along a longitudinal axis oriented in an axial direction withinthe sidewall groove.